﻿using log4net;
using Microsoft.Extensions.Logging;
using System;
using System.Collections.Generic;
using System.IO;
using Velocity4Net.Ctx;
using Velocity4Net.Runtime.Parser;
using Velocity4Net.Runtime.Parser.Node;

namespace Velocity4Net.Runtime.Directives
{

    /*
     * Licensed to the Apache Software Foundation (ASF) under one
     * or more contributor license agreements.  See the NOTICE file
     * distributed with this work for additional information
     * regarding copyright ownership.  The ASF licenses this file
     * to you under the Apache License, Version 2.0 (the
     * "License"); you may not use this file except in compliance
     * with the License.  You may obtain a copy of the License at
     *
     *   http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing,
     * software distributed under the License is distributed on an
     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
     * KIND, either express or implied.  See the License for the
     * specific language governing permissions and limitations
     * under the License.
     */



















    /**
     * Base class for all directives used in Velocity.
     *
     * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
     * @author Nathan Bubna
     * @version $Id: Directive.java 1855206 2019-03-11 11:09:53Z cbrisson $
     */
    public abstract class Directive : DirectiveConstants
    {
        private int line = 0;
        private int column = 0;
        private bool provideScope = false;
        private Template template;

        protected ILog log = null;

        /**
         *
         */
        protected RuntimeServices rsvc = null;

        /**
         * Return the name of this directive.
         * @return The name of this directive.
         */
        public abstract String getName();

        /**
         * Get the directive type BLOCK/LINE.
         * @return The directive type BLOCK/LINE.
         */
        public abstract int getType();

        /**
         * Allows the template location to be set.
         * @param line
         * @param column
         */
        public void setLocation(int line, int column)
        {
            this.line = line;
            this.column = column;
        }

        /**
         * Allows the template location to be set.
         * @param line
         * @param column
         * @param template
         */
        public void setLocation(int line, int column, Template template)
        {
            setLocation(line, column);
            this.template = template;
        }

        /**
         * returns the template in which this directive appears
         * @return template
         */
        public Template getTemplate()
        {
            return template;
        }

        /**
         * for log msg purposes
         * @return The current line for log msg purposes.
         */
        public int getLine()
        {
            return line;
        }

        /**
         * for log msg purposes
         * @return The current column for log msg purposes.
         */
        public int getColumn()
        {
            return column;
        }

        /**
         * @return The template file name this directive was defined in, or null if not
         * defined in a file.
         */
        public String getTemplateName()
        {
            return template.getName();
        }

        /**
         * @return the name to be used when a scope control is provided for this
         * directive.
         */
        public String getScopeName()
        {
            return getName();
        }

        /**
         * @return true if there will be a scope control injected into the context
         * when rendering this directive.
         */
        public bool isScopeProvided()
        {
            return provideScope;
        }

        /**
         * How this directive is to be initialized.
         * @param rs
         * @param context
         * @param node
         * @throws TemplateInitException
         */
        public void init(RuntimeServices rs, InternalContextAdapter context,
                          Node node)
        {
            rsvc = rs;
            log = rsvc.getLog("directive." + getName());

            provideScope = rsvc.isScopeControlEnabled(getScopeName());
        }

        /**
         * The Parser calls this method during template parsing to check the arguments
         * types.  Be aware that this method is called pre init, so not all data
         * is available in this method.  The default implementation does not peform any
         * checking.  We do this so that Custom directives do not trigger any parse
         * errors in IDEs.
         * @param argtypes type, Array of argument types of each argument to the directive
         * for example ParserTreeConstants.JJTWORD
         * @param t token of directive
         * @param templateName the name of the template this directive is referenced in.
         * @throws ParseException
         */
        public void checkArgs(List<int> argtypes, Token t, String templateName)
        {
        }

        /**
         * How this directive is to be rendered
         * @param context
         * @param writer
         * @param node
         * @return True if the directive rendered successfully.
         * @throws IOException
         * @throws ResourceNotFoundException
         * @throws ParseErrorException
         * @throws MethodInvocationException
         */
        public abstract bool render(InternalContextAdapter context,
                                        TextWriter writer, Node node);


        /**
         * This creates and places the scope control for this directive
         * into the context (if scope provision is turned on).
         * @param context
         */
        protected void preRender(InternalContextAdapter context)
        {
            if (isScopeProvided())
            {
                String name = getScopeName();
                Object previous = context.get(name);
                context.put(name, makeScope(previous));
            }
        }

        /**
         * @param prev
         * @return scope
         */
        protected Scope makeScope(Object prev)
        {
            return new Scope(this, prev);
        }

        /**
         * This cleans up any scope control for this directive after rendering,
         * assuming the scope control was turned on.
         * @param context
         */
        protected void postRender(InternalContextAdapter context)
        {
            if (isScopeProvided())
            {
                String name = getScopeName();
                Object obj = context.get(name);

                try
                {
                    Scope scope = (Scope)obj;
                    if (scope.getParent() != null)
                    {
                        context.put(name, scope.getParent());
                    }
                    else if (scope.getReplaced() != null)
                    {
                        context.put(name, scope.getReplaced());
                    }
                    else
                    {
                        context.remove(name);
                    }
                }
                catch (Exception cce)
                {
                    // the user can override the scope with a #set,
                    // since that means they don't care about a replaced value
                    // and obviously aren't too keen on their scope control,
                    // and especially since #set is meant to be handled globally,
                    // we'll assume they know what they're doing and not worry
                    // about replacing anything superseded by this directive's scope
                }
            }
        }

    }
}